Bug 1889157 - Do not await heartbeat.noticePromise in...

Bug 1889157 - Do not await heartbeat.noticePromise in browser_LegacyHeartbeat.js r=chumphreys a=RyanVM

Bug 1845150 refactored all usages of the notification box, including the one
used in Normandy's heartbeat implementation. These changes are not available on
ESR115. The test has been updated to not reference these changes.

Differential Revision: https://phabricator.services.mozilla.com/D206416

toolkit/components/normandy/test/browser/browser_LegacyHeartbeat.js

@@ -199,8 +199,6 @@ decorate_task(
       // We are going to simulate the timer timing out, so we do not want it to
       // *actually* time out.
       heartbeat.endTimerIfPresent("surveyEndTimer");
-      const notice = await heartbeat.noticePromise;
-      await notice.updateComplete;
 
       const telemetrySentPromise = new Promise(resolve => {
         heartbeat.eventEmitter.once("TelemetrySent", payload =>